First of all, wash the chicken pieces then make a paste of some ginger, garlic, green chilli and marinade the chicken with the above said paste. Add curd, lemon juice, salt in it. Add mustard oil to give distinct flavour to the chicken. Keep it for 1 hour.
Then, take your eggplant and make 3-4 insertion on the different sides of the eggplant and put the whole clove of garlic into it then roast the eggplant on the stove top or in oven till it completely roasted. Remove burnt skin from the eggplant. Do not remove it completely if you want to have some smoky flavour in it.
Till it getting roasted, put some ghee or butter into the pan, when it gets really hot then add fenugreek seeds to get the maximum flavour, then add some cumin seeds, put crushed ginger,garlic, green chillies then add sliced onions into the pan till it becomes little soft then add crushed kasuri methi. Now this is time to add all the spices i.e. red chilli powder, turmeric powder. Cook all the spices well till the ghee oozes out from it. Now add eggplant , cook it till the ghee oozes out . Now add your chicken in it. Stir to mix it well. Cover it for 15 mins. Before taking out from the stove top add a spoon full of ghee to enhance it taste. Put coriander and sprinkle garam masala on it.